Electrical connector for solid dielectric type coaxial lines



May 8, 1951 K. ERIKSEN ET AL ELECTRICAL CONNECTOR FOR SOLID I lllllliilrr'4 Filed June 8, 1948 DIELECTRIC TYPE COAXIAL LINES INVE'VTOR KENNETH ERIKSEN CARL W. CONC ELMAN BY wgmgg m NE Patented May 8, 1951 ELECTRICAL CONNECTOR. FOR SOLID DIELECTRIC TYPE COAXIAL LINES Kenneth Eriksen and Carl W. Concehnan, Brookfield, Conn., assignors to Hazeltine Research, Inc., Chicago, 111., a corporation of Illinois Application June 8, 1948, Serial No. 31,708

Claims.

The present invention relates to electrical connectors and, particularly, to such connectors for use with dielectric-filled types of coaxial transmission lines.

Coaxial transmission lines are widely used to translate high-frequency wave-signal energy, for example, between a wave-signal transmitter and its associated wave-signal antenna system or between a receiving antenna system and a wavesignal receiver. It frequently is desirable to provide an electrical connector between two sections of such transmission line or between the end of the line and a wave-signal apparatus coupled thereto, the connection usually being of the de tachable type.

Relatively little difficulty is experienced in the design and construction of such connectors where they are to be used with a coaxial transmission line of relatively large physical size. The inner and outer conductors of the line are then sufiiciently large that the inner and outer conductors of the connector may readily be constructed of approximately the same diameters while yet possessing adequate rigidity and mechanical strength.

However, the present-day trend is toward coaxial transmission lines of relatively small physical size, often of external diameter of the order of a quater inch or less. Electrical connectors for use with such small transmission lines have not heretofore been constructed as small as desired for certain applications and have been comparatively complex and costly.

It is an object of the present invention, therefore, to provide a new and improved electrical connector for a solid-dielectric type of coaxial transmission line.

It is an additional object of the invention to provide an electrical connector which, while of sturdy mechanical construction, may have a physical size appreciably smaller than heretofore readily obtainable.

It is a further object of the invention to provide an electrical connector of relatively simple and inexpensive construction which does not require that close mechanical tolerances be maintained during its manufacture.

It is still a further object of the invention to provide a new and improved electrical connector which may readily and quickly be assembled on, or disassembled from, a coaxial transmission line.

It is an additional object of the invention to provide a new and improved electrical connector of very small physical size for use with a small diameter coaxial transmission line yet one having a characteristic impedance at least approximately equal to that of the line.

In accordance with a particular form of the invention, an electrical connector for a soliddielectric type coaxial transmission line having an outer covering including at least a conductive sheath comprises an outer-sleeve portion and a conductive inner sleeve portion permanently supported in unitary relation with, and having a part of the length thereof in spaced concentric relation within, the outer sleeve portion to receive adjacent one end thereof an unsheathed end portion of the line and to form with the inner conductor thereof a transmission-line section. At least one of the sleeve portions has a wall of tapered longitudinal cross-section and the other of the sleeve portions has a substantially cylindrical Wall in spaced concentric relation with the one sleeve portion. The inner sleeve portion includes at the foresaid one end thereof a relatively thin wall which slips between the solid dielectric of the transmission line and the sheath thereof when the connector is assembled on the endof the line. At least one of the opposing surfaces of the sleeve portions is provided with a roughened gripping surface effective to grip the outer covering of the transmission line between the opposing surfaces to maintain the connector in assembled relation on the line.

For a better understanding of the present invention, together with other and further objects thereof; reference is had to the following description taken in connection with the accompanyingdrawing, and its scope will be pointed out in the appended claims.

The drawing shows a longitudinal cross-sectional view of an electrical connector l0 embodying the present invention. The connector I is mounted on the end of a solid-dielectric type of coaxial transmission line I I having an outer covering [2 which includes at least a conductive braided sheath l3 and may include a pliable protective covering 9 of rubber or any suitable plas-- tic such as polyvinylite. The electrical connector It] comprises an outer sleeve portion l4 having a knurled or other exterior gripping surface and a conductive inner sleeve portion i5 supported in unitary relation with and in spaced concentric relation within the outer sleeve portion I4. The sleeve portion 15 receives with a slidable close fit an unsheathed end portion of the transmission line H to form with the inner conductor ll thereof a transmission-line section having a characteristic impedance at least approximately equal to that of the line II. The extreme end IQ of the inner conductor I! constitutes the center terminal of the connector IB and an annular seat 20 at the corresponding end of the inner sleeve portion l5 the other termi nal thereof.

Means is provided for maintaining the sleeves l4 and I5 in a unitary assembly. This means comprises an exterior shoulder 2| provided on the inner sleeve l5 between the ends thereof and a curved flange 22 integral with one end of the 3 outer sleeve I4 and spun or otherwise shaped over the shoulder 2 I.

The inner sleeve portion I5 includes at one end thereof a relatively thin wall which slips between the solid dielectric 24 and the sheath I3 of the line II. In particular, this end of the inner sleeve portion I5 is in the form of an annular wall 25 of tapered longitudinal cross section with a relatively thin edge 25. The other of the sleeve portions, namely sleeve portion I4, has a substantially cylindrical wall, specifically the interior surface thereof, which is in spaced concentric relation with the sleeve portion I5. Furthermore, at least one of the opposing surfaces of the sleeve portions IA and I5 is provided with a roughened gripping surface. This surface is a transversely ribbed surface, such as by the use of screw threads 28, on the inner surface of the outer sleeve portion I4 in the preferred embodiment of the invention. This surface is effective to grip the outer covering I2 of the line II to maintain the connector in in assembled relation on the line. The end of the sleeve I4 opposite the flange 22 has a collar portion 29 of internal diameter slightly larger than the outer diameter of the transmission line II. The inner sleeve I5 also includes a second exterior shoulder 36 positioned between the ends thereof. A coupling sleeve 3|, having a knurled or other exterior gripping surface, is slidably supported on the end of the sleeve I5 and is maintained in assembled relation with the latter by a curved flange 32 which is spun or formed over the shoulder 30. The opposite end of the sleeve SI is interiorly threaded to receive an exteriorly threaded connector 35. The end of the inner sleeve I5 which is adjacent the end I9 of the line conductor has an inwardly inclined annular seat 20.

The connector 35 includes an exteriorly threaded conductive outer sleeve 31 within which is an insulator 38 axially bored to receive an inner conductor 39. One end of the insulator 38 contains an annular seat 40 into which the ex-. treme end M of the solid dielectric 24 is fitted upon the assembly of the connector 35 with the connector III. The inner insulator 38 is retained within the outer sleeve 3? by a curved flange 4 which is spun or otherwise formed over the end of the insulator while the opposite end of the insulator faces an inner flange 46 on the outer sleeve 31. That end of the conductor 39 which is adjacent the seat 40 of the insulator 38 has an axial bore 9 with longitudinal slots 48 to form resilient fingers which tightly fit the end portion I9 of the line conductor Ill. The conductor 39 is provided with an integrally formed collar 5!, which is positioned between an end of the insulator 3B and an insulating washer 5B abutting the flange 46, to maintain the conductor 39 in assembled relation within the connector 35.

The connector 35 is shown as of the panelmounting type. For this purpose, the unthreaded end of the sleeve 3! is provided with an exterior flange 52 which engages one side of a mounting panel 53 having an aperture 41 for receiving the connector. A nut 5c is threaded on the threaded end of the sleeve 31 and is tightened up against the other side of the panel 53.

To assemble the connector ID on the transmission line II, a length of the outer covering I2 of the line II is removed to expose a measured length of the solid dielectric 24. Next, a length of the solid dielectric 24 is removed from the inner conductor I! to expose a measured length of the latter, thus to provide the center terminal I9 of the connector. The end of the line II as thus prepared is pushed into the bore of the sleeve I5 while at the same time the sleeve I4 is turned or screwed on the line II. The thin edge 25 of the sleeve I5 is thereupon caused to wedge itself between the outer conductive sheath I3 and the solid dielectric 24 while the outer pliable covering 9 of the line is gripped by the screw threads 28 of the sleeve I4. The wedging action provided by the sleeve I5 aids in forcing the pliable cover 9 transversely into the threads of the sleeve I4 so that the threads may exert an appreciable gripping force on the covering.

When the coupling sleeve 3! of the connector IE! is threaded upon the outer sleeve 31 of the connector 35, the curved flange M of the latter electrically engages the annular seat 20 on the sleeve I5 and the resilient fingers of the conductor 39 firmly engage the end portion I9 of the line inner conductor to complete electrical connections through the connector. The end 41 of the solid dielectric 24 is then positioned within the seat to of the insulator 38. It will be noted that the depth of the seat 40 is sufiicient to provide a long leakage path, over the surfaces of the insulator members 2 3 and 38, between the outer and inner conductors of each connector portion. This, of course, greatly enhances the voltage-breakdown characteristics of the connector.

It will be apparent from the foregoing description of the invention that an electrical connector embodying the invention may be of relatively small physical size while yet posessing excellent electrical and mechanical characteristics. The connector is composed of a minimum number of simple parts, involves a comparatively simple construction, and thus is readily adaptable to be manufactured in large quantities at low cost. The connector is easily assembled on and disassembled from a coaxial transmission line and, when so assembled thereon, not only provides a good mechanical coupling to the line but also does not create any significant impedance discontinuity along the line, the latter feature being very important in the transmissionof veryhigh-frequency electrical energy.

While there has been described what is at present considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. An electrical connector for a solid-dielectric type coaxial transmission line having an outer covering including at least a conductive sheath comprising: an outer sleeve portion; and a conductive inner sleeve portion permanently supported in unitary relation with, and having a part of the length thereof in spaced concentric relation within, said outer sleeve portion and adapted to receive adjacent one end thereof an unsheathed end portion of said line and to form with the inner conductor thereof a transmissionline section; at least one of said sleeve portions having a wall of tapered longitudinal crosssection and the other of said sleeve portions having a substantially cylindrical wall in spaced concentric relation with said one sleeve portion;

said inner sleeve portion including at the said of said line and said sheath thereof when the connector is assembled on said line; and at least one of the opposing surfaces of said sleeve portions being provided with a roughened gripping surface effective to grip said outer covering between said opposing surfaces to maintain said connector in assembled relation on said line.

2. An electrical connector for a solid-dielectric type coaxial transmission line having an outer covering including at least a conductive sheath comprising: an outer sleeve portion; and a conductive inner sleeve portion permanently supported in unitary relation with, and having a part of the length thereof in spaced concentric relation within, said outer sleeve portion and adapted to receive an unsheathed end portion of said line and to form with the inner conductor thereof a transmission-line section of which the extreme end of said inner conductor constitutes the center terminal of said connector and the corresponding end of said inner sleeve portion the other terminal thereof; at least one of said sleeve portions having a wall of tapered longitudinal cross-section and the other of said sleeve portions having a substantially cylindrical wall in spaced concentric relation with said one sleeve portion; said inner sleeve portion including at the end thereof remote from said corresponding end adapted to receive said line a relatively thin wall adapted to slip between the solid dielectric of said line and said sheath thereof when said connector is assembled on said line; and said outer sleeve portion being provided on an inner surface thereof with a roughened gripping surface effective to grip said outer covering between said opposing surfaces to maintain said connector in assembled relation on said line.

3. An electrical connector for a solid-dielectric type coaxial transmission line having an outer covering including at least a conductive sheath comprising: an outer sleeve portion; and a conductive inner sleeve portion permanently supported in unitary relation with, and having a part of the length thereof in spaced concentric relation within, said outer sleeve portion and adapted to receive an unsheathed end portion of said line and to form with the inner conductor thereof a transmission-line section of which the extreme end of said inner conductor constitutes the central terminal of said connector and the corresponding end of said inner sleeve portion the other terminal thereof; at least one of said sleeve portions having a wall of tapered longitudinal cross-section and the other of said sleeve portions having a substantially cylindrical wall in spaced concentric relation with said one sleeve portion; said inner sleeve portion including at the end thereof remote from said corresponding end adapted to receive said line a relatively thin wall adapted to slip between the solid dielectric of said line and said sheath thereof when said connector is assembled on said line; and at least one of the opposing surfaces of said sleeve portions being provided with a transversely ribbed surface effective to grip said outer covering between said opposing surfaces to maintain said connector in assembled relation on said line.

4. An electrical connector for a solid-dielectric type coaxial transmission line having an outer covering including at least a conductive sheath comprising: an outer sleeve portion; and a conductive inner sleeve portion permanently supported in unitary relation with, and having a part of the length thereof in spaced concentric relation within, said outer sleeve portion and adapted to receive an unsheathed end portion of said line and to form with the inner conductor thereof a transmission-line section of which the extreme end of said inner conductor constitutes the center terminal of said connector and the corresponding end of said inner sleeve portion the other terminal thereof; at least one of said sleeve portions having a wall of tapered longitudinal crosssection and the other of said sleeve portions having a substantially cylindrical wall in spaced concentric relation with said one sleeve portion; said inner sleeve portion including at the end thereof remote from said corresponding end adapted to receive said line a relatively thin wall adapted to slip between the solid dielectric of said line and said sheath thereof when said connector is assembled on said line; and at least one of the opposing surfaces of said sleeve portions being provided with screw threads effective when said connector is screwed onto said end of said line to grip said outer covering between said opposing surfaces to maintain said connector in assembled relation on said line.

5. An electrical connector for a solid-dielectric type coaxial transmission line having an outer covering including at least a conductive sheath comprising: an outer sleeve portion having a substantially cylindrical inner surface; a conductive inner sleeve portion having a part of the length thereof permanently supported in spaced concentric relation within said outer sleeve portion and adapted to receive an unsheathed end portion of said line with a slidably close fit and having an internal diameter substantially equal to that of said sheath to form with the inner conductor thereof a transmission-line section having a characteristic impedance at least approximately equal to the characteristic impedance of said line, the extreme end of said inner conductor constituting the center terminal of said connector and the corresponding end of said inner sleeve portion constituting the other terminal thereof; said inner sleeve portion having a wall of tapered longitudinal cross section with a thin edge adapted to slip between the solid dielectric of said line and said sheath when said connector is assembled on said line; and said outer sleeve portion being provided on said inner surface thereof with screw threads effective to grip said outer covering between said inner sleeve and said surface to maintain said connector in assembled relation on said line.

KENNETH ERIKSEN. CARL W. CONCELMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 768,188 McIntyre et al Aug. 23, 1904 1,326,250 Brown et al Dec. 30, 1919 2,113,735 Mascuch Apr. 12, 1938 2,128,412 Harley Aug. 30, 1938 2,219,266 Hirsch Oct. 22, 1940 2,286,952 Cannon et a1 June 16, 1942 2,425,834 Salisbury Aug. 17, 1947 2,432,275 Bels Dec. 9, 1947 2,449,983 Devol Sept. 28, 1948 2,454,838 Richardson et al. Nov. 30, 1948 FOREIGN PATENTS Number Country Date 671,417 France Dec. 12, 1929 

